Dai Nippon Printing (DNP) Co Ltd developed a plastic cover sheet whose pencil hardness is as high as 9H.
The sheet is expected to replace chemically-strengthened cover glasses used for the display parts of smartphones, tablet computers, etc. DNP plans to start sample shipment in December 2012 and volume production in the first half of fiscal 2013, aiming to achieve sales of ¥10 billion (approx US$121 million) in fiscal 2014.
The cover sheet is made by forming a fingerprint-proof hard coat material on the surface of a plastic sheet substrate and a printable hard coat material on the back of the substrate. This time, DNP developed its own hard coat materials to realize a high hardness and a high flexibility at the same time, it said.
In addition to the high pencil hardness of 9H, the cover sheet has a high abrasion resistance. When a weight of 500g/cm2 was applied to the sheet 200 times with steel wool, no problem occurred, DNP said. Therefore, compared with chemically-strengthened cover glasses, the sheet is less likely to be broken when, for example, it is dropped, the company said.
Because the cover sheet is made of plastic, it has a high flexibility. The results of a mandrel test with 1.0mm- and 0.5mm-thick products were 140mm and 90mm diameters, respectively. So, it enables to freely design smartphones, tablet computers, etc, and it will be used as a cover sheet of flexible display in the future, DNP said.
As for its optical properties, the transmittance and haze of the sheet are 91.2% and 0.4%, respectively. Its thickness ranges from 0.5 to 1.5mm. In regard to its fingerprint resistance, the contact angle is 103° for water and 56° for oil.